Al-Shabab has vowed retribution on Kenya for sending troops into Somalia since 2011 to fight the militants who are waging an insurgency against Somalia's weak, Western-backed government

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A man stands amid the debris at the scene of an attack in the town of Mandera, Kenya, near the border with Somalia, Tuesday, Oct. 25, 2016. A Kenyan official says a number of people were killed in the extremist attack and that gunmen from the Somalia-based extremist group al-Shabab are suspected of carrying out the attack.

Islamic extremist gunmen from neighboring Somalia killed 12 people in an attack on non-Muslims in Kenya's northern Mandera County, an official said Tuesday.

Somalia's al-Shabab rebels claimed the responsibility for the early-morning attack on the Bishaaro Guest House, saying its fighters targeted Christians, according to the group's radio station, Andalus.

The gunmen used grenades and homemade explosives to break into the guest house and then stormed in with guns, said Mohamed Saleh, Mandera's regional commander.

Survivor Veronica Wambui, an actor with a group touring Mandera to showcase textbooks in schools, said they were asleep at around 2:30 a.m. when they heard explosions at the main gate to the guesthouse.

The attackers came in and went to room to room shooting and killing her colleagues, she said. She said she and others hid in a storeroom and the attackers set off another explosion which made the wall collapse on her.

"I could see the lights from the torch (flashlight) when they were checking out the room but the collapsed wall had covered me," said Wambui, speaking from her hospital bed where she is being treated for a bullet wound in the palm of her left hand and injuries to both her legs.

The acting troupe came from Nairobi and had been touring schools in Mandera County, which is near the border with Somalia, for about a month. Two weeks ago a watchman was killed at the guesthouse and there were rumors that the lodging was being targeted.

Al-Shabab has vowed retribution on Kenya for sending troops to Somalia since 2011 to fight the militants, who are waging an insurgency against Somalia's weak, Western-backed government. Kenyan security forces have managed to stop al-Shabab's attacks in major cities in Kenya that have killed hundreds.

However, Mandera County remains volatile. Al-Shabab militants hijacked a bus in Mandera in November 2014 and killed 28 non-Muslims on board. In December 2014 they killed 36 quarry workers. This year six people were killed in July when gunmen shot at buses and on Oct. 6 when al-Shabab gunmen killed six at a residential compound housing non-Muslims.

Al-Shabab's campaign of attacks targeting non-Muslims has had a devastating impact on education in Mandera County. Many non-Muslim teachers have asked to be transferred from the region, causing a shortage of teachers in the area.